The Duke University Marine and Freshwater Biomedical Sciences Center promotes multidisciplinary research on the mechanisms and effects of toxic chemicals in the environment, advances the use of marine and freshwater organisms as experimental models and/or biomarkers, and provides facilities and technical support to enhance research activities of human and environmental health significance. The premise on which the Center is based is that its programs will enhance research productivity and aid in the translation of basic research into applications that benefit human health. The Center is organized into Administrative, Facilities and Services, and Research Cores. The Center participants, drawn primarily from Duke University, are members of the Research Core. Although diverse in professional expertise, they share the goal of increasing our understanding of the mechanisms that underlie adverse effects of environmental toxicants. The Administrative Core maintains and extends communication between researchers who share an interest in the biomedical applications of marine and freshwater organisms or systems derived from them. This is accomplished through publication of ENVIRONS and PROGRESS REPORTS, by hosting and making known the results of meetings and conferences, and by integrating activities and programs of the Center. The Facilities and Services Core supports research activities of Center participants by making technical expertise and equipment available and by maintaining and upgrading existing equipment. Center staff aid researchers in methods development, use and maintenance of equipment, and generation of reports that make new equipment and research proposals competitive. The Research Core provides technical and logistic support for exploratory and innovative studies by Center participants and Visiting Scholars. This support is an impetus for new program development and for advancement of ongoing studies in the areas of oxygen and metal toxicity, non-mammalian models for toxicological studies, and human health consequences of ecosystem perturbations.